Objective To investigate the clinical features and complications of aged patients with pneumonia from our hospital in the past 3 years in order to provide a basis for the reasonable clinical comprehensive treatment of these patients. Methods Clinical data of 112 aged patients over 70 years old with pneumonia hospitalized in our department from January 2007 to December 2009 were collected and analyzed. The clinical features and complications were analyzed. Causative factors of pulmonary infection, common complications, symptoms, signs, and imaging characteristics were analyzed for community-acquired pneumonia and hospital-acquired pneumonia. Results The incidence of hospital-acquired pneumonia was in an increased trend in the cohort, accounting for 54.6%. The patients with hospital-acquired pneumonia had non-typical symptoms and signs, higher mortality, more complications, and severe pathogenic conditions and more changeful radiological features when compared with those of community-acquired pneumonia. The top 5 complications were multiple organ failure, heart failure, respiratory failure, multiple electrolyte disturbances, and alimentary anemia. The first 5 precipitating factors were aspiration, regurgitation, cerebral infarction, heart failure and surgical procedures. Conclusion The incidence of pneumonia especially the hospital-acquired pneumonia in the elderly is increasing year by year in the past 3 years in our hospital. Meanwhile, the hospital-acquired pneumonia usually has non-typical symptoms and signs, and is commonly combined with severe complications. It is of great importance to prevent precipitating factors and give reasonable combined treatment for these patients.